OKLAHOMA CITY, OKLAHOMA. Many athletes suffer from gastroesophageal reflux disease (GERD) in which stomach contents move into the esophagus causing heartburn (acid reflux). Researchers at the University of Oklahoma now report that weightlifters are considerably more prone to acid reflux than are competitive cyclists and runners. Their experiment involved 10 runners, 10 weightlifters, and 10 cyclists. Each had electrodes placed in their stomach and esophagus enabling continual measurement of acidity (pH) in the two areas. Runners and cyclists exercised for 60 minutes at 65% maximal heart rate and 20 minutes at 85% maximal heart rate. Weightlifters performed a series of weightlifting exercises at 65% of their 1-RM (3 sets) and 85% of their 1-RM (1 set). All exercises were performed in the fasting state as well as 45 minutes after consuming a standard meal.
The severity of acid reflux was measured as the percent of time that the pH at the esophagus electrode was
4.0 or less. Weightlifters experienced the most heartburn, 18.5% of the time in the fasting state and 35.8%
after the meal. Cyclists had heartburn 4.0% and 6.5% and runners 4.9% and 17.2% fasting and after the
meal respectively. The researchers also measured gastroesophageal reflux, that is, the movement of any
stomach content (not just acid) into the esophagus; this was defined as the total time over which the pH in
the esophagus was 5.0 or less. For weightlifters the percent of time spent experiencing gastroesophageal
reflux was 32.5% (fasting) and 49.3% (after meal). Corresponding figures were 10.4% and 11.5% for
cyclists and 8.4% and 26.8% for runners. Surprisingly, reflux was no different in weightlifters whether they
were upright or lying down and cyclists, who lean forward on their racing bikes actually had significantly less
reflux than did upright runners. This shows that the effect of gravity in helping to keep stomach contents in
the stomach is of minor, if any, significance, at least in trained athletes.